Ophiocordyceps sinensis (synonym: Cordyceps sinensis) is the most unique biological resource in China, belongs to Ascomycota, Sordariomycetes, Hypocreales, Ophiocordycipitaceae, Ophiocordyceps, and mainly originates in Tibet, Qinghai, Yunnan, Sichuan, Gansu and other snow-capped and cold highland areas with an altitude over 3,000 meters in China. Ophiocordyceps sinesis fungus infects host insect, i.e., ghost moth larva and inactivates it, and the fungus-infected inactivated insect grows under a suitable condition to form an insect (inactivated insect) and grass (fungal fruiting body) composite morphological structure which is the authentic medicinal Ophiocordyceps sinensis.
Medicinal and edible Ophiocordyceps sinensis is excellent in a plurality of functions, such as tonifying liver and kidney, benefiting vital energy, regulating various consumptive diseases. In modern medicine, Ophiocordyceps sinensis is regarded as a natural immune regulator, a “natural large combination therapy” for human health care. Ophiocordyceps sinensis may produce a variety of physiologically active substances with anti-bacterial, anti-viral, anti-tumor, anti-radiation and immune-regulating functions, and has a wide application in medicine, food and modern biotechnology, etc., especially plays an important role in traditional tonic market in China, always wins trust and favor from nationals, and realizes hot sell in Japan, Korea, Southeast Asia, the United States and other international markets.
Depletion of resources, strong demands and protection policies lead to its soaring market price. Wild Ophiocordyceps sinensis has been listed as species under national secondary protection. In order to protect Qinghai-Tibet Plateau ecology and Ophiocordyceps sinensis resources so that Ophiocordyceps sinensis better serves human health, the only option is artificial cultivation.
Artificial propagation of a host insect ghost moth (Lepidoptera, Hepialidae) of Ophiocordyceps sinensis fungi, is an important part of artificial cultivation of Cordyceps sinensis. It is reported that over 60 species of ghost moth insects are distributed in Yunnan, Tibet, Sichuan, Qinghai and Gansu. Ghost moths are holometabolous insects, the life cycle of which includes egg, larva, pupa and adult stages. The most suitable soils for growth are alpine meadow and scrubland soils. Life cycles of ghost moth species vary in different areas, but on the whole the life cycles are regular. Pupae emerge into adults in June to August every year. After mating of male and female insects, the female insects shall immediately scatter the eggs in the nearby grass or shrub vegetation. Generally each female ghost moth lays 200-800 eggs. Ghost moth larva have a tunnel-type life in natural soil and are omnivorous with plant tender roots as main food. Larvae have to go through a long period of growth and development, generally 7-9 instars (900-1300 days) for pupation, and there is a significant metagenesis phenomenon in the period. Ghost moth larvae are dormant in the soils during soil-freezing period from October every year to April of next year. Ghost moth larvae start to form pupae in late May each year, and then emerge into adults after pupa stage of 1-3 months. In the natural environment the whole generation cycle of the ghost moth insects is accomplished by comprehensive controls on multiple ecological factors including species, geographic distribution, food, vegetation, soil structure, temperature, humidity and natural enemies and the like.
In the artificial feeding process of ghost moth insects, feed quality, pathogen pollution, low survival rate of larvae, inconsistent developmental stages of male and female pupae, low mating opportunities of adults are critical constraints.